#include <stdio.h>#include <string.h>#include <stdlib.h>#include <math.h>#include <algorithm>using namespace std;int min(int a,int b){ if(a>b)a=b; return a;}int max(int a,int b){ if(a<b)a=b; return a;}struct mnod{ long long x,y;}node[5005];int dp[1000005];int main(){ int T; scanf("%d",&T); while(T--) { int n,dis,temp; scanf("%d",&n); for(int i=0;i<n;i++) { scanf("%lld%lld",&node[i].x,&node[i].y); } memset(dp,-1,sizeof(dp[0])*(node[n-1].x+2)); dp[node[0].x]=0; for(int i=1;i<n;i++) { dis=sqrt(node[i].y*node[i].y-(node[i].y-node[0].y)*(node[i].y-node[0].y)); for(int j=1;j<=dis;j++) { if(node[i].x-j<node[0].x)break; if(dp[node[i].x-j]==-1)continue; else { temp=min(node[i].x+j,node[n-1].x); if(dp[temp]==-1)dp[temp]=dp[node[i].x-j]+1; else dp[temp]=min(dp[temp],dp[node[i].x-j]+1); } } } printf("%dn",dp[node[n-1].x]); } return 0;}
